California workers’ compensation insurers’ total direct written premium (DWP) rose 3.1 percent to $7.1 billion last year, according to new data from the National Association of Insurance Commissioners (NAIC) posted by the California Department of Insurance, the California Workers’ Compensation Institute reported. The $214 million increase in aggregate premium in 2010 broke a five-year downtrend that saw California workers’ compensation premium volume plummet from an all-time high of $16.1 billion in 2004 to $6.9 billion in 2009, a decrease of more than 57 percent.